U.S. patent number 5,830,255 [Application Number 08/642,574] was granted by the patent office on 1998-11-03 for formulation of phosphorus fertilizer for plants.
This patent grant is currently assigned to The Regents of the University of California. Invention is credited to Carol J. Lovatt.
United States Patent |
5,830,255 |
Lovatt |
November 3, 1998 |
**Please see images for:
( Certificate of Correction ) ( Reexamination Certificate
) ** |
Formulation of phosphorus fertilizer for plants
Abstract
Concentrated phosphorus fertilizers are disclosed that comprise
a buffered composition of an organic acid and salts thereof and a
phosphorous-containing acid and salts thereof. The concentrated
phosphorus fertilizers can be diluted with water of pH ranging from
about 6.5 to about 8.5 at ratios of concentrate to water at about
1:40 to about 1:600 to result in a fertilizer having a pH in the
range acceptable for foliar uptake of phosphorus.
Inventors: |
Lovatt; Carol J. (Riverside,
CA) |
Assignee: |
The Regents of the University of
California (Alameda, CA)
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Family
ID: |
22709963 |
Appl.
No.: |
08/642,574 |
Filed: |
May 3, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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192508 |
Feb 7, 1994 |
5514200 |
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Current U.S.
Class: |
71/11; 71/27;
71/32; 71/41; 71/64.1 |
Current CPC
Class: |
C05B
7/00 (20130101); C05G 5/23 (20200201); C05B
7/00 (20130101); C05B 13/02 (20130101); C05B
17/00 (20130101); C05F 11/00 (20130101); C05B
7/00 (20130101); C05B 13/02 (20130101); C05B
17/00 (20130101) |
Current International
Class: |
C05B
7/00 (20060101); C05B 7/00 (20060101); C05B
015/00 () |
Field of
Search: |
;71/11,27,32,41,64.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2359077 |
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Jul 1976 |
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FR |
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2378587 |
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Jan 1979 |
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FR |
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34171331 |
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Nov 1985 |
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DE |
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291482 |
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Dec 1986 |
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JP |
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74784 |
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Mar 1992 |
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JP |
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655373 |
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Apr 1979 |
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SU |
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86/00613 |
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Jan 1986 |
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WO |
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Other References
Lovatt, C.J., "A Definitive Test to Determine Whether Phosphite
Fertilization can Replace Phosphate Fertilization to Supply P in
the Metabolism of 'Hass/ on Duke 7. A preliminary report," Proc. Of
Second World Avocado Congress, p. 224 (1992). .
Unknown, "Foliar Applications do Double Duty," Citrograph,
75(7):161 (1990). .
MacIntire et al., "Fertilizer Evaluation of Certain Phosphorus,
Phosphorous, and Phosphoric Materials by Means of Pot Cultures,"
Agronomy Journal, 42(11):543 (1950). .
Grossl et al., "Precipitation of Dicalcium Phosphate Dihydrate in
the Presence of Organic Acids," Soil Science Society of America
Journal, 55(3):670 (1991). .
Product Information Brochure for "Supa Stand Phos: Supa Protective
Pop-Up Starter," Published by Agrichem Manufacturing Ind.:
Australia, 2 pages (Aug. 1990). .
Product Information Brochure for "Supa Stand Phos: Supa Crop,"
Published by Agrichem Manufacturing Ind.: Australia, 1 page (Oct.
1990). .
Product Information Brochure for "Supa Stand Phos: Supa Protective
Pop-Up Starter," Published by Agrichem Manufacturing Ind.:
Australia, 2 pages. .
Product Information Brochure for "Kelpak: Liquid Seaweed
Concentrate," Published by Agrichem Manufacturing Ind.: Australia,
1 page. .
Product Information Brochure for "Organic Extract: Typcial
Analysis," Published by Agrichem Manufacturing Ind.: Australia, 1
page..
|
Primary Examiner: Langel; Wayne
Attorney, Agent or Firm: Dreger; Walter H. Brunelle; Jan
P.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. Ser. No. 08/192,508,
filed Feb. 7, 1994, now U.S. Pat. No. 5,514,200.
Claims
What is claimed is:
1. A concentrated phosphorus fertilizer comprising a buffered
composition comprising at least one phosphorous-containing acid or
salt thereof such that when said composition is diluted with water
having a pH of about 6.5 at a ratio of about 1 part fertilizer to
about 40 parts water, there is formed a substantially fully
solubilized use-dilution fertilizer having a foliage-acceptable pH
for phosphorus uptake.
2. The phosphorus fertilizer of claim 1 wherein said
phosphorous-containing acid is selected from the group consisting
of phosphorous acid, hypophosphorous acid, polyphosphorous acid,
and polyhypophosphorous acid.
3. The phosphorus fertilizer of claim 1 wherein said
phosphorous-containing acid or salt thereof is present in an amount
of about 30 to about 40 weight percent.
4. The phosphorus fertilizer of claim 1 wherein said buffered
composition comprises at least one organic acid or salt thereof in
an amount sufficient to form a double or multiple buffer with said
phosphorus-containing acid agent.
5. The phosphorus fertilizer of claim 4 wherein said organic acid
is selected from the group consisting of dicarboxylic acids and
tricarboxylic acids.
6. The phosphorus fertilizer of claim 4 wherein said organic acid
is citric acid.
7. The phosphorus fertilizer of claim 1 wherein said use-dilution
fertilizer a pH in the range of about 5.0 to 7.0.
8. The phosphorus fertilizer of claim 1 further comprising at least
one plant nutrient is selected from the group consisting of
nitrogen, potassium, sulfur, calcium, magnesium, boron, iron,
manganese, molybdenum, zinc, sulfur and ammonia.
9. The phosphorus fertilizer of claim 1 that is in a liquid
form.
10. The phosphorus fertilizer of claim 1 that is in a solid
form.
11. A concentrated phosphorus fertilizer comprising a buffered
composition comprising a phosphorous-containing acid or salt
thereof such that when said composition is diluted with water
having a pH as high as about 8.5 at a ratio of about 1 part
fertilizer to about 40 parts water, there is formed a substantially
fully solubilized use-dilution fertilizer having a
foliage-acceptable pH for phosphorus uptake.
12. The phosphorus fertilizer of claim 11 wherein said
phosphorous-containing acid is selected from the group consisting
of phosphorous acid, hypophosphorous acid, polyphosphorous acid,
and polyhypophosphorous acid.
13. The phosphorus fertilizer of claim 11 wherein said
phosphorous-containing acid or salt thereof is present in an amount
of about 30 to about 40 weight percent.
14. The phosphorus fertilizer of claim 11 wherein said buffered
composition comprises at least one organic acid or salt thereof in
an amount sufficient to form a double or multiple buffer with said
phosphorus-containing acid agent.
15. The phosphorus fertilizer of claim 14 wherein said organic acid
is selected from the group consisting of dicarboxylic acids and
tricarboxylic acids.
16. The phosphorus fertilizer of claim 14 wherein said organic acid
is citric acid.
17. The phosphorus fertilizer of claim 11 wherein said use-dilution
fertilizer a pH in the range of about 5.0 to 7.0.
18. The phosphorus fertilizer of claim 11 further comprising at
least one plant nutrient is selected from the group consisting of
nitrogen, potassium, sulfur, calcium, magnesium, boron, iron,
manganese, molybdenum, zinc, sulfur and ammonia.
19. The phosphorus fertilizer of claim 11 that is in a liquid
form.
20. The phosphorus fertilizer of claim 11 that is in a solid
form.
21. A concentrated phosphorus fertilizer comprising a buffered
composition comprising a phosphorous-containing acid or salt
thereof such that when said composition is diluted with water
having a pH of about 6.5 at a ratio as high as about 1 part
fertilizer to about 600 parts water, there is formed a
substantially fully solubilized use-dilution fertilizer having a
foliage-acceptable pH for phosphorus uptake.
22. The phosphorus fertilizer of claim 21 wherein said
phosphorous-containing acid is selected from the group consisting
of phosphorous acid, hypophosphorous acid, polyphosphorous acid,
and polyhypophosphorous acid.
23. The phosphorus fertilizer of claim 21 wherein said
phosphorous-containing acid or salt thereof is present in an amount
of about 30 to about 40 weight percent.
24. The phosphorus fertilizer of claim 21 wherein said buffered
composition comprises at least one organic acid or salt thereof in
an amount sufficient to form a double or multiple buffer with said
phosphorus-containing acid agent.
25. The phosphorus fertilizer of claim 24 wherein said organic acid
is selected from the group consisting of dicarboxylic acids and
tricarboxylic acids.
26. The phosphorus fertilizer of claim 24 wherein said organic acid
is citric acid.
27. The phosphorus fertilizer of claim 21 wherein said use-dilution
fertilizer a pH in the range of about 5.0 to 7.0.
28. The phosphorus fertilizer of claim 21 further comprising at
least one plant nutrient is selected from the group consisting of
nitrogen, potassium, sulfur, calcium, magnesium, boron, iron,
manganese, molybdenum, zinc, sulfur and ammonia.
29. The phosphorus fertilizer of claim 21 that is in a liquid
form.
30. The phosphorus fertilizer of claim 21 that is in a solid
form.
31. A concentrated phosphorus fertilizer comprising a buffered
composition comprising a phosphorous-containing acid or salt
thereof such that when said composition is diluted with water
having a pH as high as about 8.5 at a ratio as high as about 1 part
fertilizer to about 600 parts water, there is formed a
substantially fully solubilized use-dilution fertilizer having a
foliage-acceptable pH for phosphorus uptake.
32. The phosphorus fertilizer of claim 31 wherein said
phosphorous-containing acid is selected from the group consisting
of phosphorous acid, hypophosphorous acid, polyphosphorous acid,
and polyhypophosphorous acid.
33. The phosphorus fertilizer of claim 31 wherein said
phosphorous-containing acid or salt thereof is present in an amount
of about 30 to about 40 weight percent.
34. The phosphorus fertilizer of claim 31 wherein said buffered
composition comprises at least one organic acid or salt thereof in
an amount sufficient to form a double or multiple buffer with said
phosphorus-containing acid agent.
35. The phosphorus fertilizer of claim 34 wherein said organic acid
is selected from the group consisting of dicarboxylic acids and
tricarboxylic acids.
36. The phosphorus fertilizer of claim 34 wherein said organic acid
is citric acid.
37. The phosphorus fertilizer of claim 31 wherein said use-dilution
fertilizer a pH in the range of about 5.0 to 7.0.
38. The phosphorus fertilizer of claim 31 further comprising at
least one plant nutrient is selected from the group consisting of
nitrogen, potassium, sulfur, calcium, magnesium, boron, iron,
manganese, molybdenum, zinc, sulfur and ammonia.
39. The phosphorus fertilizer of claim 31 that is in a liquid
form.
40. The phosphorus fertilizer of claim 31 that is in a solid
form.
41. A method of providing phosphorus to a plant comprising diluting
the concentrated phosphorus fertilizer of claim 1 with water to
form a use-dilution fertilizer and applying said use-dilution
fertilizer to a plant.
42. The method of claim 41 wherein said use-dilution fertilizer is
applied to the foliage of said plant.
43. A method of providing phosphorus to a plant comprising diluting
the concentrated phosphorus fertilizer of claim 11 with water to
form a use-dilution fertilizer and applying said use-dilution
fertilizer to a plant.
44. The method of claim 43 wherein said use-dilution fertilizer is
applied to the foliage of said plant.
45. A method of providing phosphorus to a plant comprising diluting
the concentrated phosphorus fertilizer of claim 21 with water to
form a use-dilution fertilizer and applying said use-dilution
fertilizer to a plant.
46. The method of claim 45 wherein said use-dilution fertilizer is
applied to the foliage of said plant.
47. A method of providing phosphorus to a plant comprising diluting
the concentrated phosphorus fertilizer of claim 31 with water to
form a use-dilution fertilizer and applying said use-dilution
fertilizer to a plant.
48. The method of claim 31 wherein said use-dilution fertilizer is
applied to the foliage of said plant.
49. A concentrated phosphorus fertilizer comprising a buffered
composition comprising at least one phosphorous-containing acid or
salt thereof such that when said composition is diluted with water
having a pH of as low as about 6.5 at a ratio as high as about 1
part fertilizer to about 40 parts water, there is formed a
substantially fully solubilized use-dilution fertilizer having a
foliage-acceptable pH for phosphorus uptake.
50. A concentrated phosphorus fertilizer comprising a buffered
composition comprising at least one phosphorous-containing acid or
salt thereof such that when said composition is diluted with water
having a pH of as high as about 8.5 at a ratio as high as about 1
part fertilizer to about 40 parts water, there is formed a
substantially fully solubilized use-dilution fertilizer having a
foliage-acceptable pH for phosphorus uptake.
51. A concentrated phosphorus fertilizer comprising a buffered
composition comprising at least one phosphorous-containing acid or
salt thereof such that when said composition is diluted with water
having a pH of as low as about 6.5 at a ratio as low as about 1
part fertilizer to about 600 parts water, there is formed a
substantially fully solubilized use-dilution fertilizer having a
foliage-acceptable pH for phosphorus uptake.
52. A concentrated phosphorus fertilizer comprising a buffered
composition comprising at least one phosphorous-containing acid or
salt thereof such that when said composition is diluted with water
having a pH of as high as about 8.5 at a ratio as low as about 1
part fertilizer to about 600 parts water, there is formed a
substantially fully solubilized use-dilution fertilizer having a
foliage-acceptable pH for phosphorus uptake.
Description
BACKGROUND OF THE INVENTION
Fertilizers are added to the soil of crops or in some cases they
can be applied directly to crop foliage to supply elements needed
for plant nutrition. Seventeen elements are known to be essential
to the health and growth of plants. Typically, nitrogen,
phosphorus, and potassium are provided in the greatest quantity.
With increasing knowledge of the role of each of the nutrients
essential to plants, there is a better understanding of the
importance of providing a given nutrient at the appropriate stage
of phenology. To accomplish this, rapid changes in fertilizer
formulations and methods of application have been necessary.
Another factor changing fertilization formulations and methods is
due to pressure from federal, state and local regulatory agencies
and citizen groups to reduce the total amount of fertilizer in
general, and of specific nutrients in particular, being applied to
the soil. Additionally, the loss of registration of existing
synthetic plant growth regulators and organic pesticides and the
prohibitively high costs involved in the successful registration of
new ones, also plays a role in the changing arena of crop
fertilization.
The principal source of phosphorus for the fertilizer industry is
derived from the ores of phosphorus-containing minerals found in
the Earth's crust, termed phosphate rock. Elemental phosphorus does
not exist in nature; plants utilize phosphorus as the dihydrogen
phosphate ion (H.sub.2 PO.sub.4.sup.-). While untreated phosphate
rock has been used for fertilizer, it is most commonly acidulated
with dilute solutions of strong mineral acids to form phosphoric
acid, which is more readily absorbed by crops.
Until recently, phosphate and polyphosphate compounds were
considered the only forms in which phosphorus could be supplied to
plants to meet the plant's nutritional need for phosphorus. Indeed,
the only phosphite compound cited for use as a fertilizer in the
Merck Index (M. Windhols, ed., 1983, 10th edition, monograph no.
1678) is calcium phosphite (CaHPO.sub.3). No phosphite fertilizer
formulations are listed in The Farm Chemical Handbook (Meister
Publishing Co., 1993, Willoughby, Ohio 834 p.) or Western
Fertilizer Handbook (The Interstate, Danville, Ill. 288 p.)
Historically, calcium phosphite was formed as a putative
contaminant in the synthesis of calcium superphosphate fertilizers
[McIntyre et al., Agron. J. 42:543-549 (1950)] and in one case, was
demonstrated to cause injury to corn [Lucas et al., Agron. J.
71:1063-1065 (1979)]. Consequently, phosphite was relegated for use
only as a fungicide (Alliete.RTM.; U.S. Pat. No. 4,075,324) and as
a food preservative.
More recently, it has been shown that plants can obtain phosphorus
from phosphite [Lovatt, C. J., Mar. 22, 1990, "Foliar phosphorus
fertilization of citrus by foliar application of phosphite" In:
Citrus Research Advisory Committee (eds) Summary of Citrus
Research, University of California, Riverside, Calif. pp 25-26;
Anon., May, 1990, "Foliar applications do double duty" In: L.
Robison (ed) Citrograph Vol. 75, No. 7, p 161; Lovatt, C. J., 1990,
"A definitive test to determine whether phosphite fertilization can
replace phosphate fertilization to supply P in the metabolism of
`Hass` on `Duke 7`:--A preliminary report" California Avocado
Society Yearbook 74:61-64; Lovatt, C. J., 1992]. Formulations based
on phosphorous acid and hypophosphorous acid, as phosphite is,
generally undergo oxidation to phosphate and thus lose the benefits
that could be derived from the use of phosphite fertilization
applications.
The phosphate and polyphosphate fertilizers currently used have a
number of properties that compromise their desirability as
fertilizers. Generally, they tend to form precipitates during
storage and shipping. This limits the ability to formulate
concentrated solutions of fertilizers. Additionally, formulations
must generally be maintained at a narrow pH range to prevent
precipitation, resulting in fertilizers that are limited to
particular uses. Another drawback of phosphate fertilizers is that
they are not readily taken up by the foliage of many plants and
must instead be delivered to the soil for uptake by plant roots.
The mobility of phosphate fertilizers in the soil is limited
leading to rapid localized depletion of phosphorus in the
rhizosphere and phosphorus deficiency of the plant. Frequent
reapplication of phosphate fertilizers is undesirable because it
leads to leaching of phosphate into the groundwater resulting in
eutrophication of lakes, ponds and streams.
Phosphate and polyphosphate fertilizers have also been shown to
inhibit the beneficial symbiosis between the roots of the plants
and mycorrhizal fungi. They tend to support the growth of algae and
promote bacterial and fungal growth in the rhizosphere, including
the growth of pathogenic fungi and other soil-borne pests.
Even though phosphorus, once in the plant, is very phloem mobile
(i.e. readily moving from old leaves to young tissues), phosphate
is poorly absorbed through the leaves of most plant species. This
is unfortunate because successful foliar phosphorus feeding would
result in the application of less phosphate fertilizers to the soil
and reduce phosphorus pollution of the ground water.
Accordingly, there is a need for a phosphorus fertilizer that can
be utilized in irrigation systems and applied to foliage without
the formation of precipitates that reduce nutrient availability and
uptake by the plant and plug emitters and sprayers. There is also a
need for new methods of fertilizer application that allow nutrients
in a readily available form to be supplied at the exact time the
plant needs them. This need includes the facility of a foliar
product to be sold in a single formulation for use as a
concentrated material for airplane or helicopter application or as
a dilute solution for ground spray application and yet able to be
maintained at a suitable pH range optimal for leaf uptake despite
the need to be diluted prior to application.
Additionally, there is a demand for phosphorus fertilizers that
have the facility to be used as liquids or solids (granule or
powder). There is also a demand for fertilizers that do more than
just supply nutrients. It is desired that the fertilizers also have
demonstrated plant growth regulator activity, increase the plants'
resistance to pests, promote plant health in general and root
health in particular, increase the production of allelopathic
compounds, increase pre- and post-harvest quality, improve stress
tolerance, enhance beneficial symbioses, and improve yield over
existing traditional soil or foliar fertilizers.
SUMMARY OF THE INVENTION
Given the above-mentioned deficiencies and demands of fertilizers
in general, and of phosphorus fertilizers in particular, it is an
object of the present invention to provide phosphorus to plants in
a formulation that renders phosphorus readily available to the
plants under a number of application methods such as through soil,
foliar uptake, irrigation, and other methods.
It is also an object that the phosphorus fertilizer formulations be
conveniently formulated in concentrated solutions that are stable
during storage and shipping.
Another object of the present invention is to provide a phosphorus
fertilizer that is not as inhibitory to mycorrhizal fungi as
traditional phosphate fertilizers.
It is a further object of the present invention to provide a
phosphorus fertilizer that does not support the growth of algae to
the same degree that traditional phosphate fertilizers do.
Additional objects and features of the invention will be apparent
to those skilled in the art from the following detailed description
and appended claims.
The above objects and features are accomplished by a concentrated
phosphorus fertilizer comprising a buffered composition comprising
an organic acid and salts thereof and a phosphorous-containing acid
and salts thereof. The concentrated phosphorus fertilizer can be
diluted with water of pH ranging from about 6.5 to about 8.5 at
ratios of concentrate to water at about 1:40 to about 1:600 to
result in a fully solubilized fertilizer having a pH in a range
acceptable for foliar uptake of phosphorus.
In one embodiment, the phosphorous-containing acid is selected from
the group consisting of phosphorous acid, hypophosphorous acid,
polyphosphorous acid, and polyhypophosphorous acid and the organic
acid is preferably selected from the group consisting of
dicarboxylic acids and tricarboxylic acids such as citrate.
In one embodiment, the concentrated phosphorus fertilizer is an
essentially clear liquid devoid of precipitate that can be diluted
at a ratio of about 1:40 to about 1:600 with water having pH of
about 6.5 to about 8.5, to result in a fertilizer having a pH of
about 5.0 to about 7.0, and more preferably from about 5.5 to about
6.5, to facilitate the uptake of phosphorus by a variety of
plants.
A method of providing phosphorus to plants is also disclosed. The
method comprises diluting a concentrated phosphorus fertilizer
comprising a buffered composition comprising an organic acid and
salts thereof and a phosphorous-containing acid and salts thereof
with water to form a substantially fully solubilized use-dilution
fertilizer having a pH in a range acceptable for foliar uptake of
phosphorus, and applying the fertilizer to the plant foliage.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides phosphorus fertilizers essentially
devoid of phosphate. The fertilizer comprises a double or multiple
buffer system of organic acids and their salts with a
phosphorous-containing acids and their salts. The formulation
stabilizes the phosphorous against oxidation to phosphate. Suitable
phosphorous-containing acids are phosphorous acid and
polyphosphorous acid, based generally on the formula H.sub.3
PO.sub.3, and hypophosphorous acid and polyhypophosphorous acid,
based generally on the formula H.sub.3 PO.sub.2. Phosphite, the
salt of phosphorous acid, has properties that are known to be
beneficial to crop production. It is taken up through the foliage
of avocado and citrus, two species which classically do not take up
phosphate through their foliage. Phosphite has fungicidal
properties with regard to some species of pathogenic fungi:
Rhizoctonia solani, Botrytis cinerea, Piricularia oryzae,
Plasmopora viticola, Phytophthora cinnamomi, and Phytophthora
parasitica. Recently, it has been demonstrated that phosphite also
serves as a source of metabolically active phosphorus in plants.
The properties of phosphite that make it desirable as a fertilizer
are enhanced when it is formulated according to the present
invention as a double or multiple buffer with phosphorous acid,
hypophosphorous acid, polyphosphorous acid and/or
polyhypophosphorous acid and their respective salts and organic
acids and their salts per this invention.
Suitable organic acids have the formula R--COOH or R--COO.sup.-
where R is hydrogen or a carbon-containing molecule or group of
molecules. Suitable organic acids are those that maintain the
phosphite ion in a substantially fully solubilized form upon
dilution with water at pH varying from about 6.5 to about 8.5 and
that result in a use-dilution fertilizer having a
foliage-acceptable pH for phosphorus uptake. Preferred organic
acids are dicarboxylic and tricarboxylic acids.
By the term "substantially fully solubilized" it is meant that upon
dilution, the phosphite does not precipitate, or at least not
appreciably, so as to affect administration of the liquid product
to the plant foliage, and thus is in a form available to the plant.
With present phosphite fertilizers, there is a tendency for
phosphite to precipitate if diluted with alkaline water, thereby
rendering the phosphite in a form that is unavailable to the plant
for uptake. By the term "foliage-acceptable pH for phosphorus
uptake", it is meant a pH that allows phosphorus to be absorbed by
the plant without causing damage to the foliage. A
foliage-acceptable pH for phosphorus uptake usually ranges between
about 5.0 to about 7.0, and preferably between about 5.5 to about
6.5. Phosphorus is most readily taken up by foliage at pH 6.0.
Depending on the plant species, a pH below 5.0 can cause damage to
leaves and/or the flowers and/or fruit. At higher pH, between about
7.0 to about 7.5, there is reduced uptake of nutrients, although
generally there is no plant damage. A pH between about 7.5 and 8.0,
depending on the plant species, plant damage may result. A pH
greater than 8.0, generally causes damage to the plant in addition
to reducing uptake of the nutrients. Accordingly, suitable organic
acids are those that help provide a "buffered composition" having
the desired pH range. This means that a "use-dilution fertilizer"
having an acidic to neutral pH (pH 5.0 to 7.0) can be achieved upon
high dilutions (up to about 1/600) of the concentrated fertilizer
with highly alkaline water (up to a pH of about 8.5).
Organic acids that meet this criteria include but not limited to
intermediates in the Kreb's Tricarboxylic Acid Cycle, amino acids
such as glutamic acid and aspartic acid, vitamin acids such as
ascorbic acid and folic acid, and their respective salts.
Particularly preferred organic acids are dicarboxylic and
tricarboxylic acids selected from the group consisting of citrate,
pyruvate, succinate, fumarate, malate, formate, oxaloacetate,
citrate, cis-aconitate, isocitrate, and .alpha.-ketoglutarate.
Citrate is a particularly preferred organic acid because of it is
relatively inexpensive and readily available.
These formulations allow the maintenance of continued solubility,
and thus availability for uptake by plants, of phosphorus, with or
without other nutrients, over a significantly wide range of
concentrations and pHs. The increased solubility of these
formulation over that of phosphate or phosphite fertilizers makes
it possible to prepare fertilizers with a greater concentration of
phosphorus per unit volume than traditional phosphate or
polyphosphate fertilizers. The resulting pH of these fertilizers
varies significantly depending upon the pH of the water used, thus
affecting the availability of the nutrients for foliar uptake. In
contrast, the highly concentrated fertilizers of the present
invention, which can be diluted with water at a ratio of about
1:600, allow for more cost effective shipping, handling, and
application. They result in greater uptake of phosphorus by the
canopy of plants than traditional phosphate or recent phosphite
fertilizers not formulated in this manner.
The formulations provided herein also make it possible to formulate
various combinations of other essential plant nutrients or other
inorganic or organic compounds as desired and maintain their
solubility when used over a wide range of concentrations and pHs,
which is not possible for present phosphate or phosphite
fertilizers. For example, boron, manganese, calcium, iron and other
elements can be provided at relatively high concentrations in these
formulations. Thus, these phosphorus fertilizers also enhance the
canopy uptake of other mineral nutrients essential to plants. They
can be used as a canopy application to improve pre- and
post-harvest crop quality.
Formulations can also prepared with copper. However, when high
concentrations of copper are used, the copper is not fully
solubilized. In this situation, the insoluble copper is desirable
as it prevents rapid uptake of the copper and thus minimizes the
potential for copper toxicity. As the insoluble copper is rewetted
over night by dew, dissolution occurs so that additional copper is
taken up. The buffering capacity of the formulation maintains the
pH at a foliage-acceptable pH when the insoluble copper is rewetted
so that conditions are optimal for uptake and are benign to the
plant tissues. While copper is an element essential to plants, it
is required in only small amounts. In relation to nitrogen, plants
require, in general, 10,000- to 75,000-fold less copper. Provided
to the foliage of the plant at the rate provided by this
formulation, copper is a very effective fungicide, in addition to
being a plant nutrient and fertilizer.
In addition to the above-mentioned advantages, the formulations
disclosed have a direct benefit to the environment. Because the
formulations allow successful foliar feeding of phosphorus to a
number of plants that do not effectively take up phosphorus when
supplied in phosphate or polyphosphate forms, and because these
formulations enhance the uptake of other nutrients, they are
cost-effective and can replace less efficient, traditional
soil-feeding methods. This results in reducing phosphate pollution
of the groundwater and eutrophication of freshwater ponds, lakes
and streams.
The phosphorus fertilizers disclosed herein can also be
advantageously applied through the soil or by irrigation systems as
solid (granular) or liquid formulations. These formulations can be
used at pHs sufficiently low to clean irrigation lines and alter
the pH of the soil to solve alkalinity problems while supplying
essential nutrients to plants. Example 2, below discloses a
suitable formulation for irrigation application. With irrigation
application, the fertilizer flowing through the irrigation system
will typically have a pH lower than about 2.5, usually less than
about pH 1.5. The low pH is designed to supply phosphorus while
killing bacteria and algae (slime) which plug irrigation lines,
thus cleaning the lines. The low pH also dissolves calcium
carbonate deposits at and around the emitters, and solubilizes the
calcium carbonate so Ca.sup.2+ is available to the plant. Once
delivered to the soil near the plant, sufficient water is applied
to achieve a pH suitable for phosphorus uptake by the plant. The
form in which the phosphorus is supplied in these formulations is
more mobile than phosphate fertilizers or than the simple salts of
phosphorous acid, and thus more available and more readily taken up
by the roots of plants. An advantage of these formulations is that
the form in which phosphorus is supplied does not inhibit the
development of mycorrhizal fungi to the same degree that
traditional phosphate fertilizers do. The present compositions can
also be formulated with certain nutrients in addition to phosphorus
that are readily absorbed through soil applications at pH of about
5.5 to about 7.0. Such nutrients include nitrogen, calcium,
magnesium, potassium, molybdenum, boron, and sulfur.
Another advantage with the phosphorus fertilizers disclosed herein
is that they do not support the growth of green algae to the same
degree that traditional phosphate fertilizers do. This is of
significant importance to agriculture, commercial nurseries, the
ornamental and cut flower industry, and the home and garden
industry, as it will prevent the growth of green algae which
typically proliferate and plug irrigation emitters, foul pots and
benches, and provide a niche for the growth of pathogenic bacteria
and fungi. These formulations also endow the phosphorus fertilizer
with anti-viral, anti-bacterial and anti-fungal activity. This
bacterialcidal activity in a phosphorus fertilizer makes it
possible to use this fertilizer to inhibit ice-nucleating bacteria
to thus protect plants from frost damage.
Methods of Preparation
The phosphorus fertilizers are prepared by first forming solutions
of the phosphorous and organic acids. Other desired nutrients can
then be added with constant stirring. The amount of phosphorous
relative to organic acid is not critical, as long as appropriate
buffering and solubility are achieved. Generally the amount of
organic acid that is added will depend upon the form in which the
nutrient elements are added. For example, if calcium is to be added
in the form of calcium hydroxide (a base), then the acid form of
the organic acid, for example citric acid, would be used rather
than its salt, citrate. In addition to the desired nutrients, other
additives, that are known in the fertilizer industry, can be added.
These include, for example, wetting-agents, surfactants, spreaders,
stickers etc., and are described in The Farm Chemical Handbook,
supra (incorporated herein by reference). The fertilizer
compositions can also be prepared as solid formulations, identical
to the liquid ones by simply leaving out all of the water. The
properties are the same as the liquid formulations but have the
additional advantage of weighing less for the same amount of
nutrient.
Methods of Application
The fertilizer is applied according to crop-specific
recommendations which will depend upon the application method
(foliar, soil, irrigation, etc.), time of application, rate of
application, and product formulation. Crops that will benefit from
the fertilizer include, but are not limited to, avocado, citrus,
mango, coffee, deciduous tree crops, grapes and other berry crops,
soybean and other commercial beans, corn, tomato, cucurbits and
cucumis species, lettuce, potato, sugar beets, peppers, sugarcane,
hops, tobacco, pineapple, coconut palm and other commercial and
ornamental palms, hevea rubber, and ornamental plants.
In addition to the foliar, soil, and irrigation application methods
mentioned above, the present fertilizer may prove beneficial to
certain crops through other application methods. For example, trunk
paints or other methodologies may provide for a continuous low
supply of fertilizers, such as, for example, "intravenous" feeding
as practiced in the boron nutrition of soybeans.
In order that the invention described herein may be more fully
understood, the following examples are set forth. All chemicals
used were of analytical reagent quality and approximately 100% by
weight unless otherwise specified. All formulations are expressed
in terms of weight to volume. It should be understood that these
examples are for illustrative purposes only and are not to be
construed as limiting the scope of the invention in any manner.
EXAMPLE 1
A formulation was prepared of 1 gallon of 0-40-0 fertilizer with
3.86 lbs H.sub.3 PO.sub.3, 1.34 lbs tripotassium citrate, 1.34 lbs
of trisodium citrate, and 4.0 lbs of 58% ammonium hydroxide. The
components were dissolved in water with constant stirring. This
single formulation can be used at a rate of 2 quarts in as little
as 20 gallons of water of pH 6.5 to 8.5 up to 300 gallons of water
of pH 6.5 to 8.5 and maintain a pH between 5.5 to 6.5 without the
formation of any precipitate.
EXAMPLE 2
A formulation was prepared of 1 gallon of 0-40-0 fertilizer with
3.86 lbs H.sub.3 PO.sub.3 and 0.5 lbs citric acid. This formulation
is stable at pH 1.0 or less and is designed for application through
the irrigation system. It is stable against oxidation and
precipitation when supplied through the irrigation water.
EXAMPLE 3
A formulation was prepared of 1 gallon of 0-30-0 fertilizer with
74.89% elemental boron with 2.89 lbs H.sub.3 PO.sub.3, 28.67 lbs
borax (Na.sub.2 B.sub.4 O.sub.7.10 H.sub.2 O), 17.16 lbs boric acid
(H.sub.3 BO.sub.3), 1.54 lbs H.sub.2 SO.sub.4 and 2.67 lbs citric
acid. A solution of the phosphorous and citric acid was first
prepared, then the other elements were added with constant
stirring. This formulation can be used at the rate of 2 quarts in
as little as 20 gallons of water of pH between 6.5 to 8.5 up to 300
gallons of water of pH 6.5 to 8.5 and maintain a pH between 5.5 to
6.5 without the formation of any precipitate.
EXAMPLE 4
A formulation was prepared of 1 gallon of 0-30-0 fertilizer with
21.57% Zn and 23.22% Mn with 2.89 lbs of H.sub.3 PO.sub.3, 7.92 lbs
ZnSO.sub.4, 7.16 lbs Mn(H.sub.2 PO.sub.2).sub.2.H.sub.2 O, 0.61 lbs
citric acid and 0.87 lbs 58% NH.sub.4 OH. This formulation can be
used at the rate of two quarts in as little as 20 gallons of water
of pH between 6.5 to 8.5 up to 300 gallons of water of pH between
6.5 to 8.5 and maintain a pH between 5.5 to 6.5 without the
formation of any precipitate.
EXAMPLE 5
A formulation was prepared of 1 gallon of 0-30-0 fertilizer with
5.4% Ca. It was packaged in a two-container system where 1 gallon
of solution A contained 2.89 lbs H.sub.3 PO.sub.3, 0.68 lbs
Ca(OH).sub.2, and 0.28 lbs citric acid, and 1 gallon of solution B
contained 0.16 lbs Ca(OH).sub.2, 0.60 lbs KOH, 3.34 lbs 58%
NH.sub.4 OH, 0.28 lbs citric acid, and 0.67 lbs EDTA
(ethylenediaminetetraacetic acid). Two quarts of solution A can be
added to as little as 20 gallons of water of pH between 6.5 to 8.5
up to 300 gallons of water of pH between 6.5 to 8.5 followed by the
addition of two quarts of solution B. The final solution is between
pH 5.5 to 6.5 and without precipitation.
A formulation of 1 gallon of 0-30-0 fertilizer with 4.32% Ca can be
made without requiring EDTA. This formulation is also packaged in a
two-container system where 1 gallon of solution A contains 2.89 lbs
H.sub.3 PO.sub.3, 0.67 lbs Ca(OH).sub.2 and 0.28 lbs of citric
acid, while 1 gallon of solution B contains 2.67 lbs of 58%
NH.sub.4 OH, 0.6 lbs KOH. Two quarts of solution A can be added to
as little as 20 gallons of water of pH between 6.5 to 8.5 up to 300
gallons of water of pH between 6.5 and 8.5 followed by the addition
of two quarts of solution B. The final pH of the solution is
between 5.5 and 6.5 and without precipitation.
EXAMPLE 6
A formulation was prepared of 1 gallon of 0-30-30 fertilizer with
2.89 lbs H.sub.3 PO.sub.3, 2.99 lbs KOH, and 0.84 lbs citric acid.
Two quarts can be added to as little as 20 gallons of water of pH
between 6.5 to 8.5 and up to 300 gallons of water of pH between 6.5
and 8.5. The pH of the final solution is between 5.5 and 6.5
without precipitation.
EXAMPLE 7
A formulation was prepared of 1 gallon of 0-30-0 fertilizer having
4.8% iron with 2.89 H.sub.3 PO.sub.3, 1.75 lbs iron-citrate, 0.74
lbs KOH, 0.62 lbs NaOH, and 2.00 lbs of 58% NH.sub.4 OH. Two quarts
of the formulation can be added to as little as 20 gallons of water
pH 6.5 to 8.5 and up to 300 gallons of water of pH 6.5 to 8.5. The
pH of the final solution is between 5.5 to 6.7 without
precipitation.
EXAMPLE 8
A formulation was prepared of 1 gallon of 0-30-0 fertilizer having
23.22% manganese with 2.89 H.sub.3 PO.sub.3, 7.16 lbs. Mn(H.sub.2
PO.sub.2).sub.2, and 0.133 lbs. sodium citrate. Two quarts of the
formulation can be added to as little as 20 gallons of water pH 6.5
to 8.5 and up to 300 gallons of water of pH 6.5 to 8.5. The pH of
the final solution is between 5.5 to 6.5 without precipitation.
EXAMPLE 9
A formulation was prepared of 1 gallon of 0-30-0 fertilizer having
57% copper with 2.89 H.sub.3 PO.sub.3, 7.3 lbs Cu(OH).sub.2 (57%
Cu), and 1.34 lbs of 58% NH.sub.4 OH. Two quarts can be added to as
little as 20 gallons of water of pH 6.5 to 8.5 up to 300 gallons of
water of pH 6.5 to 8.5. The pH of the final solution is between 5.5
to 6.5. The copper is not fully soluble, however this is desirable
in that it prevents the rapid uptake of copper when applied to
plant foliage.
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